Guide rail protective device



- May 27,1969

F. SARTORIO GUIDE RAIL PROTECTIVE DEVICE Filed April 5, 1967 United States Patent Int. Cl. F16c l7/00, 21/00, 29/00 U.S. Cl. 308--3.5 2 Claims ABSTRACT OF THE DISCLOSURE The invention relates to precision apparatus wherein there are incorporated precision guide rails, which rails must be kept free from dust. In accordance with the invention, there is provided a particular form of tubular sheath within which the rail is housed and through resilient wall parts of which a movable part may extend to communicate with a further part guided by the said rail. The invention also specifies the specific construction of particularly advantageous resilient sheath parts and the specific construction of particularly advantageous parts which are well suited to moving therethrough in accordance with the stated object of the invention.

The present invention relates to the prevention of dust deposits on the guide rails of precision apparatus, such as measuring apparatus wherein such rails are provided to guide a part which is precision movable. The invention particularly relates to dust exclusion from such apparatus wherein the rails are designed to guide a member over a substantial stroke length.

By the term dust as used herein it is of course intended to mean dirt, grit or any other fine substance, the presence of which on the rails of such a machine would be undesirable.

In order eifectively to protect very long rails of such a machine against dust and the said other agents, it is necessary to provide a suitable protection arrangement and conventional arrangements such as bellows, slidable plates or telescopic tiles are in practice relatively ineffectual.

It is an object of the invention to provide a device which is effective regardless of the length of the rails and which affords an at least substantially perfect closure of the region to be protected.

According to these and further objects of the invention, there is provided a device for preventing the deposit of dust on guide rails in precision apparatus, wherein the said device comprises a tubular sheath in which a said rail may be enclosed, the said sheath having a rigid longitudinal component or components with a longitudinal slit therein or therebetween extending parallel to the said rail, the said slit being closed by two longitudinal strips of resilient material such as or having the properties of, vulcanized rubber, the edges of which strips overlap one another along the sheath length and are mutually separable to allow the passage therebetween of a movable part of the said precision apparatus and to sealingly engage such a part irrespective of its position along the rail and sheath length.

In order positively to ensure mutual contact of the strip edges, so as thoroughly to prevent access of dust or the like to the rail, eachsaid strip is provided with a plurality of leaf springs arranged to press the edges of the said strips one against the other.

These and other objects and advantages of the invention will be clear from the following description, given with reference to the accompanying drawings which are by way of example and in which:

FIG. 1 is a perspective view of a device according to the invention, the device being shown in this figure with a movable member of a precision apparatus which is guided by a rail and rail-engaging arrangement, also of the apparatus, removed from view;

FIG. 2 is a cross sectional view of the device of FIG. 1 taken along the line IIII of FIG. 3, the said movable member of the apparatus being herein diagrammatically represented; and

FIG. 3 is a plan view of the device of FIGS. 1 and with parts thereof broken away.

In the drawings there is shown a rail 5 mounted on a supporting girder 4, the said rail being that component of the precision apparatus which is to be protected from dust by the device according to the invention. The supporting arrangement for the said movable member guided by the said rail comprises a carrier for the elements which engage on the rail, these elements being for instance and as shown, a plurality of rollers 6. This carrier is formed from a flattened prismatic body 28 which is firmly secured to the aforementioned movable member, which latter is referenced 7. This said body 28 has two wedge-shaped wing extensions 29, 30 which lie in use parallel with the rail 5 and have a function which will be later detailed.

As shown, a longitudinal tubular sheath for the rail comprises the combination of longitudinal rigid walls 18, 19 secured by ribs 20, 21 to the girder 4 and a pair of suitable dimensioned longitudinal strips 22, 23 formed from vulcanized rubber or a material with similar properties. The free longitudinal edges 24, 25 of the strips 22, 23 respectively overlap to form a seal between the said strips.

In order to enhance and maintain this seal a plurality of leaf springs 26 are arranged on the outside of the strip 22 and are each secured at one end to the wall 18. These springs press the strip 22 towards the inside of the sheath and thus, of course, against the strips 23. Similarly, there are also provided a plurality of leaf springs 27 on the inside of the strip 23, these springs being secured to the wall 19 and arranged to press the strip 23 towards the outside of the sheath and thus against the strip 22.

In use, the said extensions 29, 30 of the body 28, and of course the :body 28 itself, are arranged between the edges 24, 25 of the strips 22, 23. The said edges are pressed by the springs 26, 27 against the body 28 and the extensions 29, 30, and such pressure results in the sealing of the inside of the sheath enclosing the rail 5 from the outside thereof. In accordance with the objects of the invention, such sealing of course prevents dust and the like from the atmosphere from reaching the interior of the sheath and thus the rail 5 therein.

The faces of the wedge-shaped extensions 29, 30 are inclined with respect to the plane of the rail 5 and if desired helical in form. This inclination and dimensioning facilitates the opening and closing of the edges 24, 25 of the strips 22, 23 around the body 28 as it moves along the rail and sheath length. This is of course because one said extension leads the body 28 while the other trails behind it.

Various modifications of the invention are of course possible-within the scope of the appended claims.

What I claim is:

1. A device for preventing the deposit of dust on guide rails in precision apparatus, the device comprising: a tubular structure in which a guide rail is enclosed, wherein the tubular structure comprises:

(a) a means supporting the rail,

(b) at least one rigid longitudinal wall secured to the rail supporting means, a longitudinal slot disposed adjacent the rigid wall and extending along the length of the wall parallel to the rail,

(c) two longitudinal strips of resilient material mounted on the tubular structure adjacent to and closing the longitudinal slot, the strips each having longitudinal edge portions, the edge portions disposed adjacent the slot and separably arranged in overlapping relation to one another, whereby the edges of the resilient members sealingly engage the precision apparatus as it passes through the tubular structure;

(d) a plurality of leaf springs mounted on the tubular structure in biasing contact with one surface of each of the resilient members, the springs arranged to bias the edges of the strips into secure sealing contact with each other and the precision apparatus.

2. A device as in claim 1 wherein the precision apparatus comprises a carrier body, rail engaging elements mounted on the body in moving contact with the rail, a guided element attached to the body and arranged externally of the tubular structure, whereby the guided element is to be precision guided by movement of the body to the tubular structure, the extensions mounted on the body so as to slidingly engage the edges of the resilient strips, whereby the extensions serve to separate the strips While maintaining sealing contact with the edges as the carrier body moves along the slot.

References Cited UNITED STATES PATENTS 2,239,714 4/1944 Hammell 5115 2,251,233 7/ 1941 Rosenberger 5 l-9 2,344,476 3 1944 Turnbull 519 MARTIN P. SCHWADRON, Primary Examiner.

along the rail, wing-like extensions attached to the carrier 15 FRANK SUSKQ, Assistant Examiner.

body so as to extend longitudinally from the body parallel 

